#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
using namespace std;
const int maxn = 110;
int mp[maxn][maxn];
int main()
{
    int n,m,x,y;
    cin>>n>>m>>x>>y;
    printf("%d %d\n",x,y);
    for(int i = 1;i<=m;i++){
        if(i!=y) printf("%d %d\n",x,i);
    }  
    int t=m,t1=m;
    for(int i = 1;i<=n;i++)
	{
        if(i!=x){
            printf("%d %d\n",i,t);
            for(int j = 1;j<=m;j++)
			{
                if(j!=t)
				{
                    t1=j;
                    printf("%d %d\n",i,j);
                }
                
            }
            t=t1;
        }
    }

}

